福建永安大湖岩溶塌陷形成机制与塌陷模式研究

Study on the Formation Mechanism and Collapse Model ofDahu Basin in Yongan,Fujian Province

为探讨大湖岩溶盆地岩溶塌陷形成机制及塌陷模式,通过实地调查和实测地质剖面,采用野外钻探、取样、室内试验分析,对研究区的岩溶塌陷成因及机制进行综合分析,提出区内岩溶塌陷机制模型。研究表明,大湖镇坑源村塌陷主要是因区内矿坑涌排水,使塌陷区的地下水水位降低和改变流向,地下水原有的浮托作用减弱直至产生失托,并产生冲蚀及土体流变,在有地下溶洞发育且上覆土层较薄处发生地面岩溶塌陷。在对大湖镇坑源村发生的多起地面塌陷成因详细分析的基础上,提出“失托—土体流变效应”的致塌模式。

Based on the field investigation and actual geological profile,field drilling,sampling and laboratory test analysis,this paper analyzes the cause comprehensively and proposes the mechanism model of karst collapse in the Dahu karst basin.The research shows that the collapse of Kengyuan village in Dahu town is mainly due to the mine drainage,which reduces the groundwater level and changes the flow direction within the area.The original buoyancy force of groundwater decreased and the support disappeared gradually,leading the erosion,soil rheology and the underground karst caves collapsed where the overlying soil layer is thin.According to the detailed analysis on the factors of most ground collapses in Kengyuan village,Dahu Town,the authors proposed the collapse model of“support loss and soil rheology effect”.